1. Field of the Invention
The present invention relates to a transportation system which transports a material to be processed in the vacuum processing apparatus and a vacuum processing apparatus adapted to transport a material to be processed to a processing stage in a vacuum processing apparatus, where vacuum treatments such as heating, film forming, dry-etching and so on are carried out.
2. Description of the Related Art
As a vacuum film forming apparatus which is one of conventional vacuum processing apparatuses, there has been known one as shown in FIGS. 15 and 16. Namely, the vacuum film forming apparatus has a supporting means 2 for supporting a material to be processed 1 (hereinbelow, referred to simply as a substrate) such as a base plate and so on, transportation rollers 3 provided at both sides of the supporting means 2 to be driven by means of a chain, a pair of guide rails 4 placed in a vacuum processing apparatus Rv and cam followers 5 mounted on the supporting means 2 to exert a pressing force to drive the supporting means 2 downwardly, whereby the supporting means 2 is caused to move along the guide rails 4 by means of the transportation rollers 3 while the rising of the supporting means 2 is suppressed, and the substrate is subjected to a film forming treatment at a film forming position (not shown).
In such a vacuum film forming apparatus, since the cam followers 5 to prevent the supporting means 2 from rising are used, a surface pressure exerted between the transportation rollers 3 and the guide rails 4 is fairly high. Further, a lubricant can not be applied between them in consideration of adverse effect to the film forming treatment due to the evaporation of the lubricant in the vacuum processing apparatus. Accordingly, when the supporting means 2 is moved, dust D such as metallic powder caused by the friction between the transportation rollers 3 and the guide rails 4 flies, and the dust D possibly deposits on a portion where the film forming treatment is to be carried out to the substrate 1. On account of this, there arise problems that the thickness of the film on the substrate 1 is uneven, and pin holes are resulted in the film to thereby deteriorate the quality of final products.
The above-mentioned problems arise not only in the vacuum film forming apparatus, but also in all kinds of vacuum processing apparatuses.